Lifting-jack.



E. JJOUMMINGS.

LIPTING JACK.

APPLIOATION TILED JULY 30, 1912.

Patented June 17,1913.

JiveraQr 2 SHEETS-SHEET l.

E. J CUMMINGS.

LIFTING JACK.

APPLICATION FILED JULY 30,1912.

' Patented June 17, 1913.

2 SHEETS-SHEET 2.

,55 Edward J;

COLUMBIA PLANOORAFH co., WASHINGTON, 0. c.

EDWARD J. CUMMINGS, OF CHICAGO, ILLINOIS.

LIFTING-JAGK.

Specification of Letters Patent.

Patented June 17, 1913.

Application filed July 30, 1912. Serial No. 712,298.

To all whom it may concern:

Be it known that I, EDWARD J. CUMMINGS, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a new and useful Improvement in Lifting-Jacks, of which thefollowing is a specification.

My invention relates to an improvement in the class of lifting-jackswherein the lifting-bar is raised through the medium of means engagingit and connected with a handle operative to actuate said means.

The primary object of my invention is to provide improved mechanism forcontrolling the bar, in lowering it, against the weight of the loadthereon,'and a readily-operative device for throwing said controllingmeans out of action for adapting the operating handle, by working it, toraise the bar.

In the accompanying drawings, Figure 1 is a vertical sectional view of alifting-jack provided with my improvements, showing the bar andoperating lever in their raised positions, the section being taken online 1, Fig. 1; Fig. 2 is a similar View of the same, showing the leverlowered to the point from which to release the raised lifting-bar; Fig.3 is a view of the lifting-jack in elevation; Fig. 4: is a section online 4, Fig. 2, through the operating lever, and on line 1*, samefigure, through the standard, showing the mechanism therein inelevation, and Figs. 5 and 6 are enlarged sections respectively on lines5 and 6, Fig. 3.

The hollow standard 7 is provided with a lateral chamber-formingenlargement 8 extending downwardly from its upper end, as in otherlifting-jacks of the present type. The lifting-bar 9, shown to beprovided with a head 10, works in the standard through its upper end,and is formed in its back with a longitudinal groove 11 to admit a stud12 projecting into it from the adjacent wall of the standard forguiding, in its vertical movements, the bar 9, which has formed on itsforward face a rack 13 extending from the lower end of the bar part wayto its opposite end. In the opposite walls of the chamber 8 is supporteda shaft 14 having a square enlargement 14: about which fits aratchet-wheel 15, and a circular enlarge ment 14 and the shaft carriesor has formed on it adjacent to the wheel, a pinion 16 engaging theteeth 13. The operating lever 17 which has a socket in its outer end fora handle 17', is bifurcated at its inner end, as shown, and the shaftpasses transversely through openings in the forked end of the lever,which loosely fit, respectively, about the shaft-section ofrelatively-small diameter and the enlargement 1 1 A pawl 18 is pivotedto the lever to extend between the arms forming its forked end and engage the ratchet 15, whereby lowering the lever, with the pawl engagingthe ratchetwheel, turns the latter for turning the pinion to engage therack 13 and raise the lifting-bar.

The parts, as thus far described, need involve no features of novelty.

On one side of the pawl 18 projects an approximately triangular, orcam-like, head 19, for the purpose hereinafter explained.

Along one side of the longitudinal center of the forward lifting-barface is formed thereon a depressed series of ratchet-teeth 20 extendingfrom the upper end of the bar short of its opposite end, but past theupper end of the series of rack-teeth 13. WVith the ratchet 20cooperates a detent-pawl 21 pivoted on a shaft 22 supported in theopposite walls of the chamber 8 toward its upper end, this detent havinga tail-piece 23 extending from it; and movement of the detent backwardlyfrom the ratchet 20 is limited by a stop 21 in its path. On the shaft 22is pivotally supported, at its head 25, an arm 25 projecting through acamlike slot 26 in the face-wall of the chamber 8 and formed with anoffset 26 at its upper end. A coiled spring 27 is confined about theshaft against a side of the head 25 for the purpose hereinafterexplained. The arm 25 has a pin 28 projecting laterally from it to bearagainst the tail-piece 23,, and a shoe 29, of general triangular shape,de pends from the arm and carries in its lowermost corner alaterally-projecting pin 30 to extend, in the direction opposite that ofthe pin 28, into the path of the cam-head 19.

In the position of the parts represented in Fig. 1, the lifting-bar issustained in its raised position by the detent 21, which is held, by theweight of the load on the bar, in engagement with a tooth of the ratchet20 against the tendency of the weight of the arm 25 upon its tail-pieceto withdraw it; and the lever 17 is raised. In lowering the lever to theposition represented in Fig. 2, the head 19 on the pawl 18 rides overthe pin 30, thereby tripping the pawl by raising its free end to removeit from encountering lever.

and being obstructed by teeth of the ratchetwheel. When, in thismovement of the operating lever, the cam 19 has cleared the pin 30, thepawl drops into engagement with a tooth of the ratchet-wheel 15, asrepresented Fig, 2 or if the movement of the lever be slow, the pawlwill drop into engagement with a ratchet wheel tooth one or more spacesahead of the showing in that figure, depending on the degree of suchslowness and whether it be desired to lower the lifting-bar more or lessby each operation of the With the pawl thus engaging the ratchet-wheel,the lever is further depressed slightly to raise the lifting-barsufiiciently to-take the load off the detent, whereupon the weightuponits tailpiece of the arm 25, through the medium of the pin 28,withdraws-the detent as far as the stop 2 1 will permit, and'frees thebar, allowing it to be lowered under the control of the operator onthe'lever 17, which rises as the bar descends. v In the rise of thelever, the cam 19 rides underneath the pin 30 in its path, therebyeventually bringing the pawl again to the relative position representedin Fig. 1, and meantime, bythe engagement of the cam with the pin30,=raising the shoe 29 to lift the weight of the arm 25 off thetailpiece 23,; thereby freeing the detent and permitting it to fallby-gr-avity into engagement with the ratchet 20 for holding theliftingbartpending another depression of the lever 17, for repeating thedescribed operation.

The movements of the parts are so timed as, to free the detent to dropinto its barsustaining position just before the pawl attains theposition, relative to a ratchet-wheel tooth, in which it is representedin Fig. 1.

When it is desired to. render inoperative the mechainsm for controllingthe lowering of the bar, for enabling the lever to be worked for liftingit, the arm 25- is raised,

' by hand, in the cam-slot'26, thereby tensioning the spring 27, so thatwhen the arm attains the oflset 26 it is snapped into the latter, to beheld therein, by the recoil of the spring. 7

As will be seen, the mechanism I have provided for the load-loweringcontrol is simple and reliable in action, thoroughly safeguardingagainst accidental dropping of the lifting-bar.

-I realize that considerable variation is possible in the details ofconstruction thus specifically shown and described and I do not intendby illustratinga single specific or preferred embodiment of my inventionto be limitedithereto; my intention being in the following'claims toclaim protection upon all thenovelty there may be in my invention asbroadly as the state of'the art will permit.

What Iclaim as new and desire to secure by Letters Patent is- 1. In alifting-jack, the combination of a standard, a lifting-bar provided witha rack, a rack-engaging pinion, an operatinglever, a pawl-and-ratchetdevice operated by said lever, and having a cam on the'pawl, a detentfor engaging said bar, and mecha nism between said lever and detentacting on the cam to trip the pawl when the lever is lowered andactuated by the cam when the lever is raised to free the detent topermit it to engage the bar.

2. In a lifting-jack, the combination of a standard, a lifting-barprovided on its face with a series of rack-teeth and a depressed seriesof ratchet-teeth to one side of the center of said face, arack-engaging-pinion, an operating-lever, a pawl-and-ratchet de viceoperated by said lever and having a cam on the pawl, a gravity-detentforengaging said ratchet-teeth, and mechanism between said lever anddetentnormally tending to hold the detent out of'engagement with saidratchet-teeth and actingon the cam to trip the pawl when the lever islowered and actuated by the cam whenthe lever is raised to free thedetent to permit it to engage the bar.

3. In a lifting-jack, the combination of a standard, a lifting-barprovided with a rack, a rack-engaging pinion, an operatinglever, apawl-and-ratchet device operated by said lever and having a cam on thepawl, a detent for engaging said bar, mechanism between said lever anddetent acting on the cam to trip the pawl when the lever is lowered andactuated by the cam when the lever is raised to free the detent topermit it to en age the bar, and means for releasably holding saidmechanism out of the path of said cam when the lifting-bar isto beraised.

4:. In a liftingjack, the combination of a standard, a lifting-barprovided with a rack, a rack-engaging pinion, an operatinglever, apawl-and-ratchet device operated by said lever and having a camon thepawl, a detentfor engaging said'bar, provided with a tail-piece, and agravity arm nor: mally bearing against said tail-piece and provided witha depending shoe extend-ing into the path of said cam, whereby, inlowering the lever-to release the detent from the load, the cam tripsthe pawl, and-in. raising the lever the cam raises said arm off saidtail-piece to permit the detent to engage the lifting-bar.

5. In a lifting-jack, the combination of a standard, a lifting-barprovided with a rack, a rack-engaging pinion, an operatinglever, apawlandratchet device operated by said lever and having a cam on thepawl, a detent for engaging said bar, provided with a tail-piece, and agravity-arm having a pin projecting from it to bearuponsaid tail-piece,said arm having a depending shoe with a pin projecting therefromtintothe path of the cam, whereby, in lowering the lever to release thedetent from the load, the cam rides over the shoe-pin to trip the pawl,and in raising the lever the cam engages the shoe-pin to lift the weightof said arm ofi the tail-piece to permit the detent to engage thelifting-bar.

6. In a lifting-jack, the combination of a standard having a chamberprovided in a wall thereof with a cam-slot containing an offset, alifting-bar provided with a rack, a rack-engaging pinion, anoperating-lever, a pawl-and-ratchet device operated by said lever andhaving a cam on the pawl, a detent for engaging said bar, provided witha tail-piece, and a spring-pressed gravityarm normally bearing againstsaid tailpiece and having a depending shoe extending into the path ofsaid cam, whereby, in lowering the lever to release the detent from theload, the cam trips the pawl, and in raising the lever the cam raisessaid arm oii said tail-piece to permit'the detent to engage the,lifting-bar, said arm extending through and being adjustably confinedin said slot.

EDWARD J. CUMMINGS. In presence of- O. C. Avrsns, D. C. THORSEN.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

